Aspects of this disclosure relate to an acoustic wave resonator having at least two resonant frequencies. An acoustic wave filter can include series acoustic wave resonators and shunt acoustic wave resonators together arranged to filter a radio frequency signal. A first shunt resonator of the shunt acoustic wave resonators can include an interdigital transducer electrode and have at least a first resonant frequency and a second resonant frequency. Related acoustic wave resonators, multiplexers, wireless devices, and methods are disclosed.
Legal claims defining the scope of protection, as filed with the USPTO.
2. The acoustic wave filter of claim 1 wherein the acoustic wave filter is a band pass filter having a pass band.
3. The acoustic wave filter of claim 2 wherein the second resonant frequency is between the first resonant frequency and an edge of the pass band.
4. The acoustic wave filter of claim 3 wherein the second resonant frequency is at least 5 megahertz above the first resonant frequency.
5. The acoustic wave filter of claim 1 wherein the acoustic wave filter has a pass band corresponding to a fifth generation New Radio operating band.
6. The acoustic wave filter of claim 1 wherein the first shunt acoustic wave resonator is a surface acoustic wave resonator.
7. The acoustic wave filter of claim 1 wherein the first shunt acoustic wave resonator is a temperature compensated surface acoustic wave resonator, and a first series resonator of the series acoustic wave resonators is a second temperature compensated surface acoustic wave resonator having a thinner temperature compensation layer than the first shunt acoustic wave resonator.
8. The acoustic wave filter of claim 1 wherein the first shunt acoustic wave resonator is a multilayer piezoelectric substrate surface acoustic wave resonator that includes a piezoelectric layer under the interdigital transducer electrode and a support substrate under the piezoelectric layer.
9. The acoustic wave filter of claim 1 wherein the first shunt acoustic wave resonator is a Lamb wave resonator.
10. The acoustic wave filter of claim 1 wherein the first shunt acoustic wave resonator is a boundary acoustic wave resonator.
11. The acoustic wave filter of claim 1 wherein the first shunt acoustic wave resonator has a third resonant frequency.
12. The acoustic wave filter of claim 1 wherein the shunt acoustic wave resonators include a second shunt acoustic wave resonator having a plurality of resonant frequencies.
14. The multiplexer of claim 13 wherein the interdigital transducer electrode is positioned between a first acoustic reflector and a second acoustic reflector, an outer interdigital transducer electrode finger of the first interdigital transducer electrode fingers is spaced apart from the first acoustic reflector by a first gap, and an outer interdigital transducer electrode finger of the second interdigital transducer electrode fingers is spaced apart from the second acoustic reflector by a second gap.
15. The multiplexer of claim 13 wherein the first shunt acoustic wave resonator includes a piezoelectric layer under the interdigital transducer electrode and a support substrate under the piezoelectric layer.
17. The multiplexer of claim 16 wherein the multiplexer is configured to provide filtering for at least two carriers of a carrier aggregation.
19. The method of claim 18 wherein the radio frequency signal is a fifth generation New Radio signal.
20. The method of claim 19 wherein the acoustic wave filter is a band pass filter having a pass band, and the second resonant frequency is between the first resonant frequency and a lower edge of the pass band.
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May 4, 2020
September 6, 2022
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